Intraoral scanner with moveable opto-mechanical module

ABSTRACT

An intraoral scanner comprises a light source, a moveable opto-mechanical module, an axial actuator, and an image sensor. The light source is configured to generate light that is to be output onto an object external to the intraoral scanner. The moveable opto-mechanical module comprises integrated projection/imaging optics and an exit pupil, the projection/imaging optics having an optical axis, wherein the projection/imaging optics are entirely integrated into the moveable opto-mechanical module. The axial actuator is coupled to the projection/imaging optics and configured to move the moveable opto-mechanical module comprising an entirety of the projection/imaging optics in the optical axis to achieve a plurality of focus settings. The image sensor is configured to receive reflected light that has been reflected off of the object external to the intraoral scanner for the plurality of focus settings.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of U.S. patent applicationSer. No. 17/142,064, filed Jan. 5, 2021, which is a continuation of U.S.patent application Ser. No. 16/586,744, filed Sep. 27, 2019, which is acontinuation of U.S. patent application Ser. No. 15/859,010, filed Dec.29, 2017, which claims priority to U.S. provisional patent applicationNo. 62/445,663, filed Jan. 12, 2017, all of which are hereinincorporated by reference in its entirety.

The following U.S. patent applications are herein incorporated byreference in their entirety to the same extent as if each individualpublication or patent application was specifically and individuallyindicated to be incorporated by reference: U.S. patent application Ser.No. 14/741,172, titled “APPARATUS FOR DENTAL CONFOCAL IMAGING,” filed onJun. 16, 2015, and U.S. patent application Ser. No. 14/825,173, titled“CONFOCAL IMAGING APPARATUS WITH CURVED FOCAL SURFACE,” filed on Aug.13, 2015.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference in their entirety to the sameextent as if each individual publication or patent application wasspecifically and individually indicated to be incorporated by reference.

FIELD

This disclosure relates generally to apparatuses and methods for threedimensional (3D) scanning of objects. In particular, the disclosurerelates to apparatuses and methods for three dimensional (3D) scanningof teeth in a patient's mouth.

BACKGROUND

Three dimensional scanning of an object is valuable in many clinicalapplications. For example, in the fields of orthodontics andprosthodontics, three dimensional (3D) scanning of the teeth can providevaluable information for diagnosis and treatment such as dentalrestorative and orthodontics indications. Confocal 3D scanning is one ofthe imaging technologies that may provide such information. Confocalmicroscopy may be used to perform three dimensional scanning byilluminating and observing a single nearly diffraction limited spot, forexample, by using a spatial pinhole to eliminate out-of-focus light.Confocal 3D scanning can be used to obtain images free of defocus-blurand may allow three-dimensional visualization of the object. Othersurface topology scanners have been described, but are generallyrelatively bulky and may be less comfortable or may even be difficult touse. U.S. Pat. No. 8,878,905 describes a 3D scanner for obtaining the 3Dgeometry of an object using confocal pattern projection techniques. The3D scanner disclosed therein uses a time varying pattern (or a segmentedlight source to equivalently create a time varying pattern). When thepattern is varied in time for a fixed focus plane then the in-focusregions on the object will display an oscillating pattern of light anddarkness. However, the out-of-focus regions will display smaller or nocontrast in the light oscillations.

Thus, there is a need for develop apparatuses and related methods forconfocal scanning to have a more compact size, lighter weight and lowercost than the conventional confocal scanning apparatuses.

SUMMARY OF THE DISCLOSURE

Described herein are apparatuses and methods for confocal 3D scanning ofan object, for example, at least apportion of teeth in a patient'smouth.

For example, described herein are apparatuses for confocal 3D scanningof a subject's dentation. The apparatus can comprise a confocalilluminator configured to generate confocal illumination to an object.The confocal illuminator can comprise a spatial pattern disposed on atransparent base and a light source configured to provide illuminationto the spatial pattern. The apparatus can comprise an optical systemcomprising one or more lenses and having an optical axis. The apparatuscan comprise a depth scanning module configured to be movable along theoptical axis. The apparatus can further comprise a beam splitterconfigured to transmit light beams of the confocal illuminator to theobject and reflect light beams returned from the object. The apparatuscan comprise an image sensor configured to receive light beams returnedfrom the object through the beam splitter. The apparatus can beconfigured for 3D scanning to at least a portion of the object, forexample, intraoral dental 3D scanning for all derivatives of dentalrestorative and orthodontics indications.

In general, the apparatus for confocal scanning disclosed herein cancomprise a confocal illuminator, for example, an LED illuminatedtransparency confocal illuminator. In general, the apparatus cancomprise an optical system (including projection/imaging optics)configured to illuminate the object and image the object. The opticalsystem can comprise a projection and imaging system or subsystem and anillumination subsystem (illumination optics). For example, theprojection/imaging optics system may include optical elements (lenses)and the same optical path. The apparatus can comprise a depth scanningmodule, which may comprise a compact linear actuator, for example, avoice coil motor (VCM). The apparatus can comprise a front tip, whichcan include a 45 degree back heated mirror.

For example, the portion of the optical system between the beam splitterand the front tip can be configured small enough to be disposed entirelyinto the depth scanning module. Therefore, the apparatus confocalscanning can comprise a single opto-mechanical module for imaging anddepth scanning. The single optomechanical module integrating the opticalsystem and the depth scanning module can leads to relaxed production andassembly tolerances as well as reduced manufacturing cost. The opticaldesign is suitable for LED illuminated transparency, which furtherenables low cost manufacturing. The optical system can further comprisereduced number of lenses, for example, the optical system can compriseless than 10 lenses, less than 9 lenses, less than 5 lenses, less than 3lenses, etc. The optical system (e.g., protection/imaging optics system)in any of the apparatuses described herein may provide an axialmagnification of between 5 and 20 (e.g., 11×). Furthermore, the opticalsystem disclosed herein may be less sensitive to assembly errors andthermal variations than conventional confocal optical systems because ofsimpler configuration. The apparatus can comprise the optical systemconfigured for maximum deviation from telecentricity towards divergentchief rays, for minimal front tip size. The apparatus can have anon-telecentric configuration in object space, for example, divergingconfocal beams in object space.

In general, the apparatus can further comprise a polarized beam splitterfor confocal junction. The apparatus can be configured for driftinvariant confocal conjugation. The apparatus can further supportmonolithic confocal conjugate assembly. In general, the confocalscanning apparatus can be compact, light weighted, and low cost. Forexample, the apparatus can be more compact (e.g., 2×, 3×, or 4×) andlighter (e.g., 2× or 3×) than a typical conventional confocal scannershaving the same scanning capability. The apparatus can further comprisea compact high speed image sensor. For example, the apparatus can becompact and light weighted to be handheld. The scan speed can be about5, 10, 20, 50 scans/sec or any values therebetween. For example, thescan speed can be about 10 scans/sec.

The spatial pattern on the transparent base may be static (e.g., nottime varying). The transparent base may comprise a transparency. Thebeam splitter may comprise a polarization sensitive beam splitter,wherein the spatial pattern and the transparent base are bonded onto afirst side of the beam splitter, wherein the image sensor is bonded to asecond side of the beam splitter perpendicular to the first side tomaintain stable relative position between the image sensor and thespatial pattern.

For example, the confocal illuminator may be configured such that animage of the light source is positioned at an entrance pupil of theoptical system. The spatial pattern may be disposed at a conjugate planeof the image sensor such that a position of an image of the object isinvariant to relative lateral shift of the spatial pattern to the imagesensor. An exit pupil of the optical system may be disposed for maximumdeviation from telecentricity towards divergent chief rays.

The optical system may comprise a projection subsystem and an imagingsubsystem, which may be combined into a projection/imaging system (alsoreferred to as a projection/imaging subsystem), wherein the projectionsubsystem and the imaging subsystem share the one or more lenses and asame optical path between the beam splitter and the object.

The apparatus may further comprise a front tip. The optical system(projecting/imaging optics portion of the system) between the beamsplitter and the front tip may be entirely integrated into the depthscanning module to be a single opto-mechanical module. The front tip maycomprise a folding mirror disposed at a 45 degree to the optical axis.The depth scanning module may be configured to be movable as a unitalong the optical axis for a range between 0.1 mm to 5 mm and have adepth scanning range between 5 mm to 40 mm. The front tip may have aheight less than 20 mm.

In general, disclosed herein are apparatuses for confocal scanning. Theapparatus may comprise illumination optics including a confocalilluminator configured to generate confocal illumination to the object.The apparatus can also comprise projecting/imaging optics configured toproject light (e.g., the transparency pattern) onto an object and toimage the object; the projection/imaging optics may have an opticalaxis. The projecting/imaging optics (a portion or subsystem of theoptical system) can comprise one or more lenses and an exit pupildisposed for maximum deviation from telecentricity towards divergentchief rays. The apparatus can comprise a depth scanning moduleconfigured to be movable along the optical axis. The apparatus cancomprise a beam splitter configured to transmit light beams of theconfocal illuminator to the object and reflect light beams returned fromthe object. The apparatus can further comprise an image sensorconfigured to receive light beams returned from the object through thebeam splitter.

Also described herein are methods for confocal three-dimensionalscanning that may include activating a confocal illuminator configuredto generate confocal illumination to an object, the confocal illuminatorcomprising a spatial pattern disposed on a transparent base and a lightsource configured to provide illumination to the spatial pattern. Themethod can comprise illuminating the spatial pattern, projecting thepattern onto an object and imaging the object using an optical systemcomprising one or more lenses and having an optical axis (e.g., theprojection/imaging optics). The method can comprise scanning the objectusing a depth scanning module configured to be movable along the opticalaxis. The method can comprise transmitting light from the confocalilluminator through a beam splitter to the object (via theprojection/imaging optics) and imaging light returning from the objectusing the imaging optics (e.g., again, via the projecting/imagingoptics) and using the beam splitter to direct the returning light ontoan image sensor.

The method can comprise using one or more spatial patterns on thetransparent base that are not time varying. For example, the method cancomprise using a spatial pattern in which the transparent base is bondedonto a first side of the beam splitter, wherein the image sensor isbonded to a second side of the beam splitter perpendicular to the firstside to maintain stable relative position between the image sensor andthe spatial pattern.

The method can include disposing an image of the light source (afterpassing through the transparency pattern) at an entrance pupil of theoptical system. For example, the method can comprise disposing a spatialpattern at a conjugate plane of the image sensor such that a position ofan image of the object is invariant to relative lateral shift of thespatial pattern to the image sensor. The method can comprise disposingan exit pupil of the optical system for maximum deviation fromtelecentricity towards divergent chief rays. The method can comprisescanning the object by moving the depth scanning as a unit along theoptical axis for a range between 0.1 mm to 5 mm to have a depth scanningrange between 5 mm to 40 mm.

As mentioned above, described herein are handheld apparatuses forconfocal (three-dimensional) scanning. These apparatuses (devices,systems, etc.) may be compact and lightweight, and may include an LEDbased emitter providing a reduced speckle noise. These apparatuses mayalso be used without requiring precise alignment (pre-alignment) asneeded in other systems in which an array of light spots is used toprovide confocal imaging, having a maximal alignment error that is about0.5 micrometers or less. The confocal apparatuses described herein maybe operated without the need for such precise alignment, by using acontinuous pattern instead of spots array. As described herein a simpletransparency may replace the spot array used in other systems. Ingeneral, these apparatuses may require substantially fewer elements thanprior art devices; the apparatuses described herein may eliminate theneed for one or more of: laser, color capture auxiliary illumination,and light transmitting thermal defogging means. Further, the apparatusesdescribed herein may have a reduced lens count (e.g., requiring fewerlenses, compared to the prior art). The small projection/imaging opticssystem may therefore allow a very compact apparatus, and in particularmay be used with a small axial actuator, such as a compact voice coilmotor (VCM).

The resulting optical configuration may be simpler and less sensitive toassembly error and thermal variations than prior art apparatuses. Inaddition, these apparatuses may be appropriate for straightforward colorimplementations, without the need for a separate illumination anddichroic filter.

For example, described herein are handheld apparatuses for confocalscanning that may include: a light source (e.g., one or more LEDs,including white-light LEDS, and/or a light collector and/oruniformizer); a transparency having a spatial pattern disposed thereonand configured to be illuminated by the light source; a beam splitter(e.g., a polarizing beam splitter) having a first surface and a secondsurface and an image sensor on the second surface; an imaging opticssystem (which may alternatively be referred to as a projection/imagingoptics subsystem in some variations) comprising an optical gain andfocusing lens and an exit pupil, the imaging optics system having anoptical axis; a front tip (e.g., a hollow front tip) extending from theimaging optics system in the optical axis and comprising a fold mirrorat a distal end of the hollow front tip, wherein there is no opticalsurface between the exit pupil and the fold mirror in the optical axis;and an axial scanner coupled to the imaging optics system and configuredto move the imaging optics system in the optical axis relative to thefold mirror.

Unlike prior art apparatuses, the projection/imaging optics system maybe configured to provide a deviation from telecentricity of a chief raybetween the projection/imaging optics system and the fold mirrorrelative to a scan field size of between 3 and 10 degrees. It waspreviously believed (see, e.g., U.S. Pat. No. 8,878,905) that theoptical system of a scanner should be substantially telecentric (e.g.,having an angle of less than 3 degrees, preferably much less) in thespace of the probed object (the object being scanned). In contrast, theapparatuses described herein may be non-telecentric, e.g., may deviatefrom telecentricity by a predetermined amount (e.g., between 3 degreesand 10 degrees, e.g., 8.5 degrees). The optical design of theapparatuses described herein may have a light source space that includesnon-telecentric aperture imaging such that the entire projection/imagingoptics are sufficiently compact and lightweight to be entirelytranslated axially (e.g., by a linear actuator/axial scanner such asVCM) to facilitate the depth scan.

For example, the apparatuses described herein may include an integratedprojection/imaging optics system that is moved as a whole by the driver(axial actuator such as a VCM). This again distinguishes from otherconfigurations in which a separate focusing element (which may form partof the imaging optics system) is moved separately from the rest of theimaging optics system. In general, the entire imaging optics systembetween the beam splitter and the hollow front tip is entirelyintegrated into a single opto-mechanical module that may be moved by theaxial scanner.

In any of the apparatuses described herein, the transparency may beattached to the first surface of the beam splitter (e.g., to an externalsurface) and/or may be integrally formed as surface in/on the beamsplitter in the optical axis. The spatial pattern on the transparencymay be static or time varying; in some variations the spatial pattern isnot time varying. The spatial pattern may be formed on or as part of thebeam splitter or may be bonded to the first surface of the beamsplitter. The transparency may be bonded onto the first surface of thebeam splitter and the image sensor bonded to the second surface of thebeam splitter, perpendicular to the first surface to maintain stablerelative position between the image sensor and the spatial pattern. Forexample, the beam splitter may be a polarization sensitive beamsplitter, and the transparency may be bonded onto the first surface ofthe beam splitter and the image sensor bonded to the second surface ofthe beam splitter, perpendicular to the first surface to maintain stablerelative position between the image sensor and the spatial pattern.

The apparatuses (devices, systems, and in particular the hand-heldscanners) and methods described herein may be particularly well suitedfor use as with three-dimensional scanning using structured lighttechniques and/or light-field technology. The patterns (static and/ortime-varying) that may be used with any of these apparatuses and methodsmay be configured for providing structured light imaging by projectingthe known pattern (e.g., grids, lines, bars, e.g., horizontal bars,arrays, etc.) and analyzing the manner in the pattern deforms whenstriking the target surface(s). The apparatus may calculate the depthand surface information of the object(s) in the scene. Thus, any ofthese apparatuses may be configured as structured light 3D scanners. Insome variations the wavelengths of light used may be different, anddifferent patterns of light may be applied corresponding to thedifferent wavelengths. For example, visible and/or infrared light may beused. Any of these apparatuses may be configured as “invisible” or“imperceptible” structured light apparatuses, in which structured lightis used simultaneously or concurrently without interfering with imagingat different frequencies. For example, infrared light and visible lightmay be applied and detected at high (including extremely high) framerates that alternate between two different patterns. The patterns may becomplimentary or opposite (e.g., in which the dark regions in a firstpattern are illuminated in the second pattern). Different wavelengths ofvisible light may be used instead or in addition to infrared light.

The methods and apparatuses described herein may also or alternativelybe configured as light field technology. Light field imaging (e.g.,plentoptic imaging) may capture information about the light fieldemanating from a scene. For example, the intensity of light in a scene,and also the direction that the light rays are traveling in space. Anyof the apparatuses and methods described herein may include an array ofmicro-lenses (e.g., placed in front of the one or more image sensors) tosense intensity, color, and directional information. In any of theseapparatuses, a micro-lens array can be positioned before or behind thefocal plane of the main len(s). Alternatively or additionally, a mask(e.g., printed film mask) may be used. A patterned mask may attenuatelight rays rather than bending them, and the attenuation may recoverablyencode the rays on the 2D sensor. The apparatus may thus focus andcapture conventional 2D photos at full sensor resolution, but the rawpixel values also hold a modulated 4D light field. The light field canbe recovered by rearranging tiles of a 2D Fourier transform of sensorvalues into 4D planes, and computing the inverse Fourier transform. Fullresolution image information can be recovered for the in-focus parts ofthe scene. A broadband mask may be placed at the lens, to allowrefocused images at full sensor resolution to be computed for somesurfaces (e.g., diffusely reflecting surfaces) including at particularwavelengths, such as near-IR. In general, the light field informationmay be used to estimate three-dimensional (e.g., depth) information fromthe image.

In any of the apparatuses described herein, the apparatus may beconfigured such that an image of the light source is positioned at anentrance pupil of the projection/imaging optics system. The entrancepupil may be part of the projection/imaging optics system, or may bebetween the projection/imaging optics system and the beam splitter, orit may be separate from the projection/imaging optics system.

The front tip may be configured to be removable from the rest of theapparatus, including a housing covering the light source, beam splitter,etc. The housing may include a handle portion with a grip and/or userinterface (controls), such as buttons, switches, etc. The front tip maybe hollow, particularly along the optical axis between the exit pupil ofthe projection/imaging optics system and the fold mirror. The front tipmay be configured to snap onto the rest of the apparatus (e.g., thehousing) and/or screw, friction fit, magnetically couple, etc. The fronttip may be single-use or reusable, including sterilizable (e.g.,autoclavable, for example, formed of a material that may be exposed totemperatures in excess of 100° C., including 121° C. or greater, withoutdeforming or damaging after continuous exposure for greater than 15minutes). Alternatively or additionally, these apparatuses may beconfigured for use with a removable/disposable sleeve that may fit overthe front tip (including, in some variations but not all, over theoptical exit at the distal end/side of the tip through which the teethmay be imaged).

In any of the apparatuses described herein the fold mirror may include aback heated defogging mirror. The fold mirror may redirect the opticalaxis of the apparatus out of a side window/exit for imaging teeth. Thefold mirror may be disposed at a 45 degree to the optical axis at thedistal end of the hollow front tip (or between an angle of 30° and 60°,35° and 55°, 40° and 50°, etc.).

The entire apparatus, and/or the hollow front tip may be compact;generally having a size that is less than 140 mm×20 mm×20 mm (e.g.,length, width, thickness). For example, the hollow front tip portion maybe 80 mm×16 mm×16 mm or less (length, width, thickness).

In general, the projection/imaging optics system may be axially moved toscan an object. For example, the projection/imaging optics system may beconfigured to be movable as a unit along the optical axis for a rangebetween 0.1 mm to 5 mm and have a depth scanning range between 5 mm to40 mm.

As mentioned, the hollow front tip may have a height of 20 mm or less(e.g., 20 mm or less, 17 mm or less, 16 mm or less, 15 mm or less, 14 mmor less, 13 mm or less, etc.). The Field of view may be between 20×20 mmand 12×12 mm (e.g., between 18×14 mm or between 14×14 mm, etc.).

Because of the features described herein, including consolidating thespatial pattern of the transparency on the beam splitter, using anintegrated projection/imaging optics system and/or having a maximumdeviation (e.g., between 3-10°) from telecentricity towards divergentchief rays, the apparatus may be relatively lightweight. For example,the apparatus may have a total weight of 300 gram or less, e.g., 250 gor less, 200 g or less 180 g or less, etc.). In addition, the diameterof the projection/imaging optics may be 15 mm or less.

For example, described herein are handheld apparatuses for confocalscanning that include: a light source; a transparency having a spatialpattern disposed thereon and configured to be illuminated by the lightsource; a beam splitter having a first outer surface to which thetransparency is attached and a second outer surface and an image sensoron the second outer surface; an integrated projection/imaging opticssystem comprising an optical gain and focusing lens and an exit pupil,the projection/imaging optics system having an optical axis; a hollowfront tip extending from the projection/imaging optics system in theoptical axis and comprising a fold mirror at a distal end of the hollowfront tip, wherein there is no optical surface between the exit pupiland the fold mirror in the optical axis; and an axial scanner coupled tothe projection/imaging optics system and configured to move the entireprojection/imaging optics system in the optical axis relative to thefold mirror; wherein the projection/imaging optics system is configuredto provide a deviation from telecentricity of a chief ray between theprojection/imaging optics system and the fold mirror relative to a scanfield size of between 3 and 10 degrees.

Also described herein are methods for confocal three-dimensionalscanning. Any of these methods may include using any of the apparatusesdescribed herein for scanning. For example, described herein are methodsfor confocal 3D scanning that include: illuminating a spatial pattern(either static or moving) on a first side of a beam splitter andprojecting the spatial pattern down an optical axis, through the beamsplitter, through an projection/imaging optics system (e.g., through aprojection/imaging optics subsystem, such as an integratedprojection/imaging optics system comprising an optical gain and focusinglens and an exit pupil), out of the exit pupil of the projection/imagingoptics system, and though a front tip extending from theprojection/imaging optics system to a fold mirror at a distal end of thehollow front tip, without passing through an optical surface between theexit pupil and the fold mirror in the optical axis; projecting thespatial pattern on a target (e.g., a tooth or other dental target);transmitting light (e.g., reflected light, florescent light, etc.) fromthe target back through the hollow tip, into the projection/imagingoptics system, through the beam splitter and into an image sensor on asecond side of the beam splitter; and scanning the target by axiallymoving the entire projection/imaging optics system in the optical axisrelative to the fold mirror; wherein the projection/imaging opticssystem is configured to provide a deviation from telecentricity of achief ray between the projection/imaging optics system and the foldmirror relative to a scan field size of between 3 and 10 degrees.

Scanning may be performed by moving the entire projection/imaging opticssystem as a unit along the optical axis, e.g., for a range between 0.1mm to 5 mm, to scan at a depth of scanning range between 5 mm to 40 mm.Any appropriate rate of scanning may be used, including scanning at 10Hz or greater (e.g., 15 Hz, 20 Hz, etc.).

In general, the spatial pattern may be any appropriate pattern,including patterns that are time varying or not time varying.

Illuminating the spatial pattern may comprise illuminating atransparency that is bonded onto a first side of the beam splitter. Theimage sensor may be bonded to a second side of the beam splitterperpendicular to the first side to maintain stable relative positionbetween the image sensor and the spatial pattern. Any of these methodsmay also include disposing the spatial pattern at a conjugate plane ofthe image sensor such that a position of an image of the object isinvariant to relative lateral shift of the spatial pattern to the imagesensor.

The methods described herein may also include disposing an image of thelight source at an entrance pupil of the optical system.

Any of these methods may also include disposing an exit pupil of theoptical system for maximum deviation from telecentricity towardsdivergent chief rays.

In general, the methods described herein may include determining aconfocal position by maximum correlation.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe claims that follow. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 schematically illustrates one example of a compact apparatus for3D confocal scanning of an object as described herein.

FIG. 2 schematically illustrates an example of a compact apparatus for3D confocal scanning of an object (in this example, the light source isconfigured to illuminates a pattern on a transparency in Kohlerillumination mode).

FIG. 3A schematically illustrates a depth scanning module of theapparatus for confocal scanning such as the apparatus shown in FIG. 1 ,in a near-focus position.

FIG. 3B schematically illustrates the depth scanning module of theapparatus for confocal scanning such as the apparatus shown in FIG. 1 ,in a mid-focus position.

FIG. 3C schematically illustrates the depth scanning module of theapparatus for confocal scanning such as the apparatus shown in FIG. 1 ,in a far-focus position.

FIG. 4A illustrates an example of a compact apparatus for confocalscanning comprising a hollow front tip with a field of view (FOV) 18×14mm, as described herein. Note that the dimensions provided are forillustrative purposes only.

FIG. 4B illustrate an example of a compact apparatus for confocalscanning comprising a hollow front tip with a field of view (FOV) 14×14mm, as described herein. Note that the dimensions provided are forillustrative purposes only.

FIG. 5 schematically illustrates the non-telecentricity of an opticalsystem as described herein for a compact apparatus for confocal 3Dscanning.

FIG. 6 schematically illustrates an example of a confocal focal planemodule of an apparatus for confocal scanning where a transparency andimage sensor are bonded directly to a beam splitter or mounted on afixture relative to the beam splitter.

FIG. 7A illustrates an example of a disordered spatial pattern that maybe used as part of a compact apparatus for 3D confocal scanning asdescribed herein.

FIG. 7B illustrates an example of an ordered spatial pattern that may beused as part of a compact apparatus for 3D confocal scanning asdescribed herein.

FIG. 8 illustrates an example of a method for confocal three-dimensionalscanning as described herein.

DETAILED DESCRIPTION

The present disclosure now will be described in detail with reference tothe accompanying figures. This disclosure may be embodied in manydifferent forms and should not be construed as limited to the exampleembodiments discussed herein.

Described herein are compact apparatuses for confocal 3D scanning. Theseapparatuses can include confocal illuminator configured to generateconfocal illumination to an object. The confocal illuminator cancomprise a spatial pattern disposed on a transparent base (transparency)and a light source configured to provide illumination of the spatialpattern so that it can be projected onto an object. The apparatus cancomprise an optical system (including projection/imaging optics)comprising one or more lenses and having an optical axis. The apparatusmay also include illumination optics for illuminating apattern/transparency forming the spatial pattern. The apparatus cancomprise an axial scanner (e.g., a depth scanning module) that isconfigured to be move the projection/imaging optics system along theoptical axis. The apparatus may include a beam splitter configured totransmit light from the light source (after passing through the pattern)to the object and reflect light returning from the object onto animaging sensor. Thus, the apparatus may include an image sensorconfigured to receive light returning from the object (via theprojection/imaging optics) through the beam splitter. The apparatus canbe configured for 3D scanning to at least a portion of the object, forexample, intraoral dental 3D scanning for all derivatives of dentalrestorative and orthodontics indications.

The apparatuses for confocal scanning disclosed here can include aconfocal illuminator, for example, an LED illuminated transparencyconfocal illuminator. The apparatus can include an optical systemconfigured project the light passing through the transparency (e.g.,pattern) onto the object and image the object. The optical system mayinclude a projection/imaging system or subsystem including projectionoptics and imaging optics. For example, the projection optics and theimaging optics can be configured to share the same optical elements(lenses) and the same optical path. The apparatus can comprise the depthscanning module, which comprise a compact linear actuator, for example,a voice coil motor (VCM). The apparatus can comprise a front tip, whichcan include a 45 degree back heated defogging fold mirror. The opticalsystem between the beam splitter and the front tip can be configuredsmall enough to be disposed entirely into the depth scanning module.Therefore, the apparatus confocal scanning can comprise a singleopto-mechanical module for projection, imaging and depth scanning. Thesingle optomechanical module integrating the optical system and thedepth scanning module can leads to relaxed production and assemblytolerances as well as reduced manufacturing cost. The optical design maybe suitable for an LED illuminated transparency, which further enableslow cost manufacturing. The optical system can further therefore have areduced lens count, for example, the optical system can comprise lessthan 10 lenses, less than 9 lenses, less than 5 lenses, less than 3lenses, etc., compared to other confocal scanning systems. Furthermore,the optical system disclosed herein may be less sensitive to assemblyerrors and thermal variations than conventional confocal optical systemsbecause of simpler configuration. The apparatus can comprise the opticalsystem configured for a desired deviation from telecentricity towardsdivergent chief rays, for minimal front tip size. The apparatus can havea non-telecentric configuration in image and source space.

The apparatus can further comprise a polarized beam splitter as part ofa confocal junction. The apparatus can be configured for drift invariantconfocal conjugation. The apparatus can further support monolithicconfocal conjugate assembly.

In general, these apparatuses may include an integratedprojection/imaging optics system in which the entire projection/imagingoptics system (e.g., the projection/imaging optics subsystem) is movedaxially to scan (rather than just a focusing lens). Although moving theentire compound projection/imaging optics system in order to scan issomewhat counterintuitive, it may provide a benefit in reduced overalldimension of the apparatus, particularly in combination with the aprojected spatial pattern and a configuration in which the system has adeviation from telecentricity for a chief ray between theprojection/imaging optics system and the fold mirror relative to a scanfield size of between 3 and 10 degrees. Because of the featuresdescribed herein, these apparatuses may be more compact (e.g., 2×, 3×,or 4×) and lighter (e.g., 2× or 3×) than a typical conventional confocalscanners having the same scanning capability. For example, the apparatuscan be compact and light weighted to be handheld. The apparatus canfurther comprise a compact high speed image sensor. The scan speed canbe about 5, 10, 20, 50 scans/sec or any values therebetween. Forexample, the scan speed can be about 10 scans/sec.

FIG. 1 schematically illustrates one example of a compact apparatus 100for confocal scanning of an object. The apparatus can comprise aconfocal illuminator 101 (light source and/or illumination optics)configured to generate confocal illumination that may be projected ontoan object. The apparatus may include a spatial pattern disposed on atransparent base, for example, a transparency 105 or a transparent glassplate. The light source and any illumination optics may be configured toprovide illumination through the spatial pattern and may include a lightcollector/reflector. For example, the light source can be an LED lightsource (with, e.g., a reflector behind it to direct light through thepattern). A conventional confocal spot array light source such as laserdiode can be replaced by the LED light source. For example, theapparatus can comprise an LED based emitter, which can reduce specklenoise. The spatial pattern can comprise an array of segments to achievespot illumination. The apparatus can further comprise a light collectoror a light uniformizer to create uniform illumination over the pattern.The apparatus can further comprise a condensing lens to condense lightbeams of the light source. The apparatus can comprise a white LED lightsource readily available for color model capture and rendering, whichcan enable straightforward color implementation.

The apparatus can comprise a beam splitter 109 and an image sensor 111.The beam splitter may be configured to transmit light beams of theconfocal illuminator to the object and reflect light beams returned fromthe object to the image sensor. The image sensor 111 may be configuredto receive light beams returned from the object. For example, the beamsplitter can be a polarization beam splitter (PBS).

The apparatus can comprise an optical system (including or consisting ofprojection/imaging optical system/subsystem 115) comprising one or morelenses (e.g., focusing optics 119), and an exit pupil 121. The opticalsystem can be configured to project light that passed through thetransparency 105 onto the object and to image the object to the imagesensor. For example, the LED light source can be configured toilluminates the transparency in Kohler illumination mode such that theimage of the LED falls on the entrance pupil of the optical system, asshown in FIG. 2 . Light leaving the imaging optical system 115(including the exit pupil) may pass through a hollow front tip 123 untilreaching a fold mirror 125 near the distal end of the front tip 123, andbe directed out of the tip to the object (e.g., teeth); light returningfrom the object travels the same path. Typically, the front tip ishollow, and the entire imaging optical system moves relative to thefront tip (e.g., there are no additional optical surfaces between theaxially movable imaging optical system and the fold mirror in the fronttip).

Referring to FIG. 2 , which, like FIG. 1 , shows an optical systemincluding a light source 201 (and may also include imaging optics, suchas a condenser lens 203 in this example) and an optical system 207(e.g., which may include a projection/imaging system). For example, theillumination subsystem can be configured to illuminate the pattern(e.g., the transparency 209) and this spatial pattern 209 may beprojected onto the object. The illuminated object can be imaged backthrough the imaging subsystem 207. The imaging subsystem can be the sameas the projection/imaging subsystem between the beam splitter and thefold mirror. The imaging path and the projection path may share the sameoptical path and same optical elements such as the one or more lenses,as shown in FIG. 1 . Thus the object can be imaged back through the sameoptical system and light reflected from the object can be directed ontothe image sensor through the beam splitter. Unlike conventional confocaloptical systems in which the imaging subsystem and the projectionsubsystem may be different, the apparatus for confocal scanningdisclosed herein can be smaller, lighter and lower cost than theconventional confocal optical system.

The imaging optical system can be mounted on a depth scanning module(axial scanner 135), as shown in FIG. 1 . For example, the opticalsystem between the beam splitter and the front tip can be entirelyintegrated and coupled to the depth scanning module for axial movementrelative to the front tip. The optical system (and in some variationsthe depth scanning module) can be integrated into a singleoptomechanical module as shown in FIG. 1 , which can lead to relaxedproduction and assembly tolerance. The axial scanner can include alinear axial actuator which can translate the optical system axially ina controlled manner, e.g., over 0.5 to 3 mm, to facilitate depthscanning. The apparatus can be configured to have high axialmagnification to enable simple depth scanning linear actuator. Axialmagnification from the transparency to the object space being scannedcan be between 4× to 30×, for example, between 5× to 12×. With the abovetranslation range and magnification range, the optics periodictranslation can yields object space depth scan coverage in the range of10 mm to 36 mm. FIGS. 3A-3C schematically illustrate axially scanning ofthe apparatus for confocal scanning in a near-focus position (FIG. 3A),a mid-focus position (FIG. 3B) and a far-focus portion (FIT>3C)respectively, showing the translation of the entire imaging opticalsystem 307, including projection/imaging optics 305. The projectedspatial pattern 301 is transmitted onto/in the object and reflectedlight is received by the sensor 303 for analysis to determine the 3Dsurface of the object.

The optical system including the combined projection/imaging subsystemcan result in simple projection optics (focus optics) andprojection/imaging optics design and reduced the number of opticalelements, such as optical lenses. The projection optics may refer to thesame optics as the imaging optics but in the projection direction (e.g.,from the light source onto the object). For example, the optical systemcan comprise less than 10, 9, 5, or 3 optical elements. For example, theoptical lenses in the optical system can have a diameter of about 5 mm,8 mm, 10 mm, 14 mm, 15 mm or any values therebetween, while the opticallenses in the conventional confocal optical system may have a diameterof about 25 mm. For example, the optical system disclosed herein furthereliminated the following elements in a typical conventional confocalscanning apparatus such as dichroic filter, micro-lens, etc. Theapparatus for confocal scanning disclosed herein is more compact,lighter weight and lower cost than a conventional confocal scanningapparatus. For example, the apparatus can have a weight of about 100,200 or 300 grams in some embodiments. For example, the apparatus canhave a size less than 150 mm×25 mm×25 mm, 140 mm×20 mm×20 mm, or 130mm×14 mm×14 mm in some embodiments.

FIG. 4A schematically illustrates an apparatus for compact confocalscanning comprising a hollow front tip with a field of view (FOV) 18×14mm. FIG. 4B illustrate an apparatus for compact confocal scanningcomprising a hollow front tip with a field of view (FOV) 14×14 mm. Asshown in FIGS. 4A and 4B, the apparatus for compact confocal scanningcan have a smaller front tip size than conventional confocal scanningapparatus. The apparatus can have a front tip height of about 14 mm witha FOV of 14×14 mm. The hollow front tip can comprise a back heateddefogging fold mirror. For example, the hollow tip can have a dimensionof about 90 mm×20 mm×20 mm, 80 mm×16 mm×16 mm, or 60 mm×14 mm×14 mm insome embodiments. These dimensions are for illustration only; otherdimensions may be used.

In general, any of the apparatuses described herein may benon-telecentric. Specifically, the projection/imaging optics system maybe configured to provide a deviation from telecentricity of a chief raybetween the projection/imaging optics system and the fold mirrorrelative to a scan field size of between 3 and 10 degrees. FIG. 5schematically illustrates an example of a non-telecentric optical systemof an apparatus for confocal scanning in one embodiment of thedisclosure. The optical system can be configured with the light sourcespace non-telecentric aperture imaging such that the optical system issufficiently compact and lightweight to be translated axially, forexample, by a linear actuator such as a voice coil motor (VCM), tofacilitate the depth scan. The exit pupil of the optical system can belocated for maximum deviation from telecentricity towards divergentchief rays, which can enable minimal size of a front tip of theapparatus. The scanned field size can be the same for all designoptions, for a specific distance from the tip, for example, a mid-rangeof a scan depth. The deviation angle from telecentricity can bedetermined by the exit pupil distance from the object focus and thefield size. The tip height can be derived by the footprint of the beamsof the light source on the folding mirror. This height can be smaller asthe exit pupil gets closer to the object focus (forward exit pupil).Possible range of deviation angle from telecentricity can be from about3 degrees to about 10 degrees. For example, the deviation angle fromtelecentricity can be about 8.5 degrees in some embodiments. Thedeviation angle from telecentricity is for the field extent in themirror folding plane, which has effect on the tip height.

FIG. 6 schematically illustrates an example of a confocal illuminator ofan apparatus for confocal scanning where a transparency (including aspatial pattern) is bonded directly to a beam splitter or mounted on afixture relative to the beam splitter in one embodiment. Thetransparency can be bonded directly onto one facet the beam splitter,for example, onto a first surface of a beam splitter (e.g., PolarizingBeam Splitter, PBS) while the image sensor can be bonded onto anotherfacet (e.g., a second surface) of the beam splitter perpendicular to thetransparency, thus maintaining stable relative position (“confocalcondition”) between the image sensor and the transparency as shown inFIG. 6 . The apparatus can be configured for drift invariant confocalconjugation. The transparency and the image sensor can be disposed onconjugate planes of the object. The apparatus can further supportmonolithic confocal conjugate assembly. Pattern based illuminationenables conjugate imaging onto the image sensor, which is invariant torelative lateral shift. The apparatus for confocal scanning can beconfigured to have position invariant correlation, which may be lesssensitive to assembly drift.

FIGS. 7A and 7B illustrates examples of spatial patterns that may beused as part of any of the compact apparatuses for 3D confocal scanningdescribed herein. FIG. 7A illustrates an example of a disordered patternof an apparatus for confocal scanning. FIG. 7B illustrates an example ofan ordered pattern of an apparatus for confocal scanning. The apparatusfor confocal scanning can comprise an illuminated pattern to replace anarray of light beams in a conventional confocal scanning apparatus. Forexample, a white LED back illuminated pattern can be used to achieveconfocal imaging. A variety of patterns can be used in the confocalilluminator, which enables design flexibility and lower signalrequirement. For example, the pattern can comprise an array of segmentsto achieve spot-illumination equivalent. The illumination spots throughthe pattern can be nearly diffraction limited. For example, the patterncan comprise an array of segments that have a size similar to pinholesin a conventional confocal microscope. For example, the pattern cancomprise an array of segments that have a diameter of about 1 μm, 10 μm,25 μm, 50 μm, 1 mm or 2 mm or any values therebetween.

For example, the apparatus for confocal scanning can further comprise anarray of detection pinholes. For example, the detection pinholes can bedisposed in a fixture between the beam splitter and the image sensor.For example, the detection pinholes can be bonded or integrated in theimage sensor. For example, the size of the pinholes can be configuredadapted to the numerical aperture (NA) of the optical system and thewavelength of the light source. For example, the size of the detectionpinholes can be further adapted to a magnification of the opticalsystem.

The confocal position can be determination by maximum correlation. Forexample, a reference pattern position can be invariant. For example, adepth position per pixel or a group of pixels of the image sensor can beassigned corresponding to the maximum signal obtained on the pixel orthe group of pixels following a depth scan. Lateral resolution need notbe compromised because all pixels within region of interest (ROI) can beused. For example, resolution can be improved by sub-pixel processing

Also described herein are methods for confocal 3D confocalthree-dimensional scanning dimensional scanning. In general, the methodcan comprise activating a confocal illuminator configured to generateconfocal illumination to an object. The method can comprise using theconfocal illuminator comprising a spatial pattern disposed on atransparent base and a light source configured to provide illuminationto the spatial pattern, and/or any additional illumination optics (e.g.,lenses).

The method can comprise illuminating a pattern, projecting the patternonto an object, and imaging the object by an optical system comprisingprojecting/imaging optics including one or more lenses and having anoptical axis. The method can comprise scanning the object by a depthscanning module configured to be movable along the optical axis. Themethod can comprise projecting beams of light from the confocalilluminator through a beam splitter, onto the object, and directinglight returning from the object onto an imaging sensor using the beamsplitter.

For example, the method can comprise using a spatial pattern on thetransparent base that is not time varying. For example, the method cancomprise using the spatial pattern and the transparent base, wherein thepattern (e.g., a transparency) is bonded onto a first side of the beamsplitter, further wherein the image sensor is bonded to a second side ofthe beam splitter perpendicular to the first side to maintain stablerelative position between the image sensor and the spatial pattern.

A method can comprise disposing an image of the light source at anentrance pupil of the optical system. For example, the method cancomprise disposing the spatial pattern at a conjugate plane of the imagesensor such that a position of an image of the object is invariant torelative lateral shift of the spatial pattern to the image sensor. Forexample, the method can comprise disposing an exit pupil of the opticalsystem for maximum deviation from telecentricity towards divergent chiefrays.

A method can comprise disposing scanning the object comprises moving thedepth scanning as a unit along the optical axis for a range between 0.1mm to 5 mm to have a depth scanning range between 5 mm to 40 mm. Forexample, the method can comprise determining a confocal position bymaximum correlation.

As discussed briefly above, the apparatuses and methods described hereinmay also be configured as structured light scanning systems and/orlight-field 3D reconstruction systems. For example, in some variationslight field data may be captured, for example, by including configuringthe imaging system as a plenotoptic apparatus, for example, by includinga plurality of micro-lenses before or after the focal plane of the mainlensing sub-system (e.g., the compact focusing optics). Thus, in somevariations the light may pass through an optical surface (themicro-lenses) between the exit pupil and the fold mirror in the opticalaxis alternatively, the micro-lenses may from part of the compactfocusing optics. A depth map may be created from the light field data,and this depth map may be used to create surfaces. Traditional stereoimaging methods may be used for depth map extraction, or depth data maybe extracted from light field cameras by combining two or more methodsof depth estimation.

FIG. 8 illustrates another example of a method as described herein. inFIG. 8 , the method for confocal three-dimensional scanning, includesfirst illuminating a spatial pattern on a first side of a beam splitterand projecting the spatial pattern down an optical axis, through thebeam splitter, through an integrated projection/imaging optics systemcomprising an optical gain and focusing lens and an exit pupil, out ofthe exit pupil and though a hollow front tip extending from theprojection/imaging optics system to a fold mirror at a distal end of thehollow front tip, without passing through an optical surface between theexit pupil and the fold mirror in the optical axis 801. The method thenincludes projecting the spatial pattern on a target 803 and transmittingreflected light from the target back through the hollow tip, into theprojection/imaging optics system, through the beam splitter and into animage sensor on a second side of the beam splitter 805. The method mayalso include scanning the target by axially moving the entireprojection/imaging optics system in the optical axis relative to thefold mirror 807, wherein the projection/imaging optics system isconfigured to provide a deviation from telecentricity of a chief raybetween the projection/imaging optics system and the fold mirrorrelative to a scan field size of between 3 and 10 degrees.

The systems, devices, and methods of the preferred embodiments andvariations thereof can be embodied and/or implemented at least in partas a machine configured to receive a computer-readable medium storingcomputer-readable instructions. The instructions are preferably executedby computer-executable components preferably integrated with the systemincluding the computing device configured with software. Thecomputer-readable medium can be stored on any suitable computer-readablemedia such as RAMs, ROMs, flash memory, EEPROMs, optical devices (e.g.,CD or DVD), hard drives, floppy drives, or any suitable device. Thecomputer-executable component is preferably a general orapplication-specific processor, but any suitable dedicated hardware orhardware/firmware combination can alternatively or additionally executethe instructions.

When a feature or element is herein referred to as being “on” anotherfeature or element, it can be directly on the other feature or elementor intervening features and/or elements may also be present. Incontrast, when a feature or element is referred to as being “directlyon” another feature or element, there are no intervening features orelements present. It will also be understood that, when a feature orelement is referred to as being “connected”, “attached” or “coupled” toanother feature or element, it can be directly connected, attached orcoupled to the other feature or element or intervening features orelements may be present. In contrast, when a feature or element isreferred to as being “directly connected”, “directly attached” or“directly coupled” to another feature or element, there are nointervening features or elements present. Although described or shownwith respect to one embodiment, the features and elements so describedor shown can apply to other embodiments. It will also be appreciated bythose of skill in the art that references to a structure or feature thatis disposed “adjacent” another feature may have portions that overlap orunderlie the adjacent feature.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, as used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, steps, operations, elements, components, and/orgroups thereof. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of explanation only unless specifically indicatedotherwise.

Although the terms “first” and “second” may be used herein to describevarious features/elements (including steps), these features/elementsshould not be limited by these terms, unless the context indicatesotherwise. These terms may be used to distinguish one feature/elementfrom another feature/element. Thus, a first feature/element discussedbelow could be termed a second feature/element, and similarly, a secondfeature/element discussed below could be termed a first feature/elementwithout departing from the teachings of the present invention.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” and “comprising” means various components can be co-jointlyemployed in the methods and articles (e.g., compositions and apparatusesincluding device and methods). For example, the term “comprising” willbe understood to imply the inclusion of any stated elements or steps butnot the exclusion of any other elements or steps.

In general, any of the apparatuses and methods described herein shouldbe understood to be inclusive, but all or a sub-set of the componentsand/or steps may alternatively be exclusive, and may be expressed as“consisting of” or alternatively “consisting essentially of” the variouscomponents, steps, sub-components or sub-steps.

As used herein in the specification and claims, including as used in theexamples and unless otherwise expressly specified, all numbers may beread as if prefaced by the word “about” or “approximately,” even if theterm does not expressly appear. The phrase “about” or “approximately”may be used when describing magnitude and/or position to indicate thatthe value and/or position described is within a reasonable expectedrange of values and/or positions. For example, a numeric value may havea value that is +/−0.1% of the stated value (or range of values), +/−1%of the stated value (or range of values), +/−2% of the stated value (orrange of values), +/−5% of the stated value (or range of values), +/−10%of the stated value (or range of values), etc. Any numerical valuesgiven herein should also be understood to include about or approximatelythat value, unless the context indicates otherwise. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. Anynumerical range recited herein is intended to include all sub-rangessubsumed therein. It is also understood that when a value is disclosedthat “less than or equal to” the value, “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “X” is disclosed the “less than or equal to X” as well as “greaterthan or equal to X” (e.g., where X is a numerical value) is alsodisclosed. It is also understood that the throughout the application,data is provided in a number of different formats, and that this data,represents endpoints and starting points, and ranges for any combinationof the data points. For example, if a particular data point “10” and aparticular data point “15” are disclosed, it is understood that greaterthan, greater than or equal to, less than, less than or equal to, andequal to 10 and 15 are considered disclosed as well as between 10 and15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11,12, 13, and 14 are also disclosed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims. The examples and illustrations included herein show, by wayof illustration and not of limitation, specific embodiments in which thesubject matter may be practiced. As mentioned, other embodiments may beutilized and derived there from, such that structural and logicalsubstitutions and changes may be made without departing from the scopeof this disclosure. Such embodiments of the inventive subject matter maybe referred to herein individually or collectively by the term“invention” merely for convenience and without intending to voluntarilylimit the scope of this application to any single invention or inventiveconcept, if more than one is, in fact, disclosed. Thus, althoughspecific embodiments have been illustrated and described herein, anyarrangement calculated to achieve the same purpose may be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments.Combinations of the above embodiments, and other embodiments notspecifically described herein, will be apparent to those of skill in theart upon reviewing the above description.

What is claimed is:
 1. An intraoral scanner, comprising: a light sourceto generate light that is to be output onto an object external to theintraoral scanner; a moveable opto-mechanical module comprising a)integrated projection/imaging optics comprising three to nine lenses andb) an exit pupil, the projection/imaging optics having an optical axis,wherein the three to nine lenses of the projection/imaging optics areentirely integrated into the moveable opto-mechanical module; an axialactuator coupled to the moveable opto-mechanical module and configuredto move the moveable opto-mechanical module comprising an entirety ofthe projection/imaging optics in the optical axis to achieve a pluralityof focus settings, wherein the three to nine lenses maintain fixedpositions relative to one another with changes in the plurality of focussettings; and an image sensor configured to receive reflected light thathas been reflected off of the object external to the intraoral scannerfor the plurality of focus settings.
 2. The intraoral scanner of claim1, further comprising a front tip extending from the projection/imagingoptics in the optical axis, wherein the front tip is to output the lightonto the object external to the intraoral scanner.
 3. The intraoralscanner of claim 2, wherein the front tip is a hollow front tip thatcomprises a fold mirror at a distal end of the hollow front tip.
 4. Theintraoral scanner of claim 3, wherein there is no optical surfacebetween the exit pupil and the fold mirror in the optical axis.
 5. Theintraoral scanner of claim 3, wherein the projection/imaging optics areconfigured to provide a deviation from telecentricity of a chief raybetween the projection/imaging optics and the fold mirror relative to ascan field size of between 3 and 10 degrees.
 6. The intraoral scanner ofclaim 3, wherein the fold mirror is disposed at a 30-60 degrees to theoptical axis at the distal end of the front tip.
 7. The intraoralscanner of claim 3, wherein the fold mirror is a heated defoggingmirror.
 8. The intraoral scanner of claim 2, wherein the front tip isconfigured to be removable from the intraoral scanner.
 9. The intraoralscanner of claim 2, wherein the front tip has a height of 20 mm or less.10. The intraoral scanner of claim 1, wherein the light source comprisesa light emitting diode (LED).
 11. The intraoral scanner of claim 1,further comprising: a beam splitter having a first surface and a secondsurface; and a transparency disposed at the first surface of the beamsplitter, the transparency comprising a spatial pattern disposedthereon, wherein the transparency is configured to be illuminated by thelight from the light source and to output patterned light comprising thespatial pattern through the beam splitter and onto the object externalto the intraoral scanner; wherein the image sensor is disposed at thesecond surface of the beam splitter, wherein the image sensor isconfigured to receive reflected patterned light that has been reflectedoff of the object and directed back through the beam splitter.
 12. Theintraoral scanner of claim 11, wherein the transparency is bonded to thefirst surface, wherein the image sensor is bonded to the second surface,and wherein as a result of the transparency being bonded to the firstsurface of the beam splitter and the image sensor being bonded to thesecond surface of the beam splitter, the image sensor maintains a stablerelative position to the spatial pattern of the transparency.
 13. Theintraoral scanner of claim 12, wherein the transparency is directlybonded to the first surface.
 14. The intraoral scanner of claim 11,wherein the spatial pattern on the transparency is not time varying. 15.The intraoral scanner of claim 11, wherein the beam splitter comprise apolarization sensitive beam splitter, and wherein the transparency isperpendicular to the image sensor.
 16. The intraoral scanner of claim 1,wherein the projection/imaging optics are configured to be movable as aunit along the optical axis for a range between 0.1 mm to 5 mm and havea depth scanning range between 5 mm to 40 mm.
 17. The intraoral scannerof claim 1, wherein a diameter of the projection/imaging optics in theoptical axis is 15 mm or less.
 18. The intraoral scanner of claim 1,wherein the projection/imaging optics have an axial magnification of 4×to 30×.
 19. The intraoral scanner of claim 1, wherein theprojection/imaging optics have an axial magnification of 5× to 12×. 20.The intraoral scanner of claim 1, wherein the projection/imaging opticscomprise combined projection optics and imaging optics that share one ormore lenses and an optical path.
 21. The intraoral scanner of claim 1,wherein the projection/imaging optics are optics of a confocal opticalsystem.
 22. The intraoral scanner of claim 1, wherein the image sensoris a light field image sensor.
 23. The intraoral scanner of claim 1,wherein an optical system comprising the projection/imaging opticscomprise comprises three to five lenses.
 24. The intraoral scanner ofclaim 1, wherein an optical system comprising the projection/imagingoptics is entirely integrated into the moveable opto-mechanical module.